Vehicle wheel comprising a signal generator function

ABSTRACT

The present invention relates to a wheel rim ( 1 ), having a wheel rim bed ( 1   a ), of a vehicle wheel having a detection system for a measurement device for detecting the rotational velocity of the vehicle wheel. The detection system comprises a marking ( 6 ), running around the circumference on the wheel rim bed ( 1   a ) or integrated therein, made of a track of marks ( 6   a,    6   b,    6   c ), which are implemented as a profile that stiffens the wheel rim bed ( 1   a ) and are detectable without contact to detect the rotational velocity when passing a sensor ( 7 ) of a measurement device to be positioned stationary next to the vehicle wheel.

Monitoring systems for the rotational velocity of the wheels areincluded in the standard equipment of modern vehicles equipped withwheels, particularly those for personal conveyance. Of these systems,ABS (antilock braking system) is the most well-known. The functionalcapability of these and other systems is a function of the precision ofthe detection of the rotational velocity of the wheel within eachrotation. In order to detect the rotational velocity as sensitively aspossible, a measurement device for detecting the rotational velocity isknown from practice, which has a disk, which is toothed, for example,rotating with the particular wheel and a fixed sensor, held on the brakecaliper of a disk brake, for example, which detects the teeth and thegaps of the toothed disk without contact. The number of teeth and toothgaps detected by the sensor at a specific rotational velocity is afunction of the diameter of the disk and the teeth and tooth gaps placedaround the circumference of the disk. For reasons of corrosion andcontamination, the teeth may not be implemented as especially fine. Theoverall space in the wheel disk, which is already restricted by housingthe brake disk with the brake caliper, also does not allow a largediameter of the toothed disk. For these reasons, the desired sensitivityin the detection of the rotational velocity of a vehicle wheel may notbe achieved using the known technology.

In addition, detection systems for the rotational velocity of a vehiclewheel, operating without contact and comprising a track of marks in theform of magnetic elements positioned on-a lateral flank of the tire ofthe vehicle wheel or on its wheel rim, which are moved past a stationarysensor of a measurement device when the vehicle wheel is rotated, areknown from the patent literature (DE 196 20 581 A1; DE 198 53 696 A1).In this case, the magnetic elements are used exclusively to detect therotational velocity of the vehicle wheel.

The present invention is based on the object of simplifying theconstruction of a sensitively reacting detection system for therotational velocity of a vehicle wheel and making it more robust whileincorporating its wheel rim.

This object is achieved using a wheel rim, having a wheel rim bed, for avehicle wheel, in which a marking running around the circumference ofthe wheel rim bed is provided on the wheel rim bed or integratedtherein, which is used for contactless detection of the rotationalvelocity when passing a sensor of a measurement device, positionedspatially next to the vehicle wheel and stationary in relation to itsrotational motion, in that the marking comprises a track of marks whichare implemented as a profile that stiffens the wheel rim bed.

In such a wheel rim of a vehicle wheel, which may have one or multipleparts and may be made of different materials, but is preferably made ofsteel, no additional elements which take up overall space are necessaryto detect the rotational velocity of the wheel, because the wheel rimbed itself is provided with the marks. This also means that they arepositioned on the largest possible circumference, with the effect that alarge number of marks may be housed here without having to implementthem as especially fine. Because of this comparatively coarseimplementation of the marks, there is also no danger that they will losetheir detectability because of contamination or other externalinfluences. In comparison to the teeth in the known, exposed tootheddisk, even during dismounting and in the dismounted state of the wheel,they are well protected from dirt and damage in its wheel disk. Inaddition, they have a stiffening effect, which allows lower wallthicknesses and therefore a lower weight at the same stiffness. This hasa positive effect on the driving comfort in the unsprung mass of avehicle wheel.

As in one of the known measurement devices for detecting the rotationalvelocity of a vehicle wheel, the sensor may also be carried by the brakecaliper of a brake system in the object of the present invention.

According to one embodiment of the present invention, the markspositioned one behind another in the track may generate a signalsequence in the sensor which is a function of the running direction. Forthis purpose, they may be divided into uniform groups.

Optically, electrically, or magnetically detectable elements aresuitable as marks. Optically detectable elements may be ribs, grooves,or beads. Amorphous, soft-magnetic alloys, such as metallic glasses, aresuitable as the material for magnetically detectable elements. Theseelements are then attached to the profile.

Furthermore, the object of the present invention is a semi-finishedproduct in the form of a sheet metal strip for manufacturing a wheel rimhaving a wheel rim bed for a vehicle wheel having one or a selection ofthe features described. In such a semi-finished product, the track ofthe marks extends in the lengthwise direction of the strip.

In the following, the present invention will be explained in greaterdetail on the basis of a drawing which illustrates an exemplaryembodiment.

FIG. 1 shows a wheel rim of a vehicle wheel in partial section,

FIG. 2 shows the wheel rim in the partial section along line II-II ofFIG. 1, and

FIG. 3 shows a semi-finished product in the form of a profile sheetmetal strip made of steel for manufacturing a wheel rim of a vehiclewheel as shown in FIG. 1.

The wheel rim 1, manufactured from sheet steel, of a vehicle wheel (notshown in its entirety) illustrated in FIG. 1 is connected by welding,for example, to a wheel disk 2. The wheel rim 1 has a wheel rim bed la.A brake disk 3, which rotates together with the vehicle wheel, and abrake caliper 4, which is positioned stationary in relation to thevehicle wheel, are provided in the overall space of the wheel disk 2 andunder the wheel rim bed 1 a.

The wheel rim 1 is manufactured from a flat sheet metal strip 5 made ofsteel, in which a track of marks 6 a, 6 b, 6 c, which are embossed intothe sheet metal strips as stiffening beads, is positioned in the metalas the marking 6. The marks 6 a, 6 b, 6 c form repeating triplet groupsof beads of different widths, whose average distance is equal. Such asheet metal strip 5 may then be manufactured continuously. Sections cutto length therefrom may then be shaped into the wheel rim 1.

In the installed state of the vehicle wheel, the marking 6 having itstriplet groups of marks 6 a, 6 b, 6 c lies opposite a sensor 7 carriedby the brake caliper 4. The marks 6 a, 6 b, 6 c and the sensor 7 form aprimary detector unit, which provides a pulse sequence for the marks 6a, 6 b, 6 c of different widths detected by the sensor 7 to ameasurement device (not shown) to detect the rotational velocity. Themeasurement device determines the rotational velocity via the angle ofrotation and/or the number of pulses per time unit. Using themeasurement device, the rotational velocity and, in addition, therotational direction of the vehicle wheel may be detected. To detect therotational direction, it is important for the sequentially followingpulses to differ from one another. This may be implemented, for example,in that the marks lying one behind another are themselves different,having different widths of grooves or beads, or the intervals ofsequential marks are different.

The marks 6 a, 6 b, 6 c may have different geometric shapes and may beimplemented differently. The stiffening grooves or beads may also carrycolored markings or reflecting elements. It is also possible,particularly in wheel rim beds made of steel, to implement them asmagnetized regions. Both active and passive marks are conceivable.

1. A wheel rim, having a wheel rim bed, for a vehicle wheel, in which amarking, which runs around the circumference of the wheel rim bed, isprovided on the wheel rim bed or integrated therein, which is used forcontactless detection of the rotational velocity when passing a sensorof a measurement device, which is positioned spatially next to thevehicle wheel and stationary in relation to its rotational movement,wherein the marking comprises a track of marks, which is implemented asa profile that stiffens the wheel rim bed.
 2. The wheel rim according toclaim 1, wherein the marks, positioned one behind another in the track,generate a signal sequence in the sensor which is a function of therunning direction.
 3. The wheel rim according to claim 1, wherein themarks are divided into uniform groups.
 4. The wheel rim according toclaim 1, wherein the marks, which form a primary detector unit with thesensor, are optically, magnetically, or electrically detectableelements.
 5. A semi-finished product in the form of a sheet metal stripmade of steel for manufacturing a wheel rim, having a wheel rim bed, fora vehicle wheel according to claim 1, in which the track of the marksextends in the longitudinal direction of the strip.